[net] On mac when reading https do not check TLS certificate

as Davix does not support it. In other words, set the Davix.GSI.CACheck
parameter in the etc/system.rootrc file to n on macos and on y
on other platforms.

Author: dpiparo

cmake/modules/RootConfiguration.cmake

@@ -420,6 +420,11 @@ if(root7)
 else()
   set(hasroot7 undef)
 endif()
+if(APPLE)
+  set(davixgsicacheck "n")
+else()
+  set(davixgsicacheck "y")
+endif()
 
 set(uselz4 undef)
 set(usezlib undef)

config/rootrc.in

@@ -591,7 +591,7 @@ Davix.UseOldClient: @useoldwebfile@
 # Davix.GSI.CAdir: /etc/grid-security/certificates
 
 # Enable/disable the Check on the peer's certificate
-# Davix.GSI.CACheck: y
+Davix.GSI.CACheck: @davixgsicacheck@
 
 # Sets the HTTP client in Grid mode, to talk to Grid HTTP SEs
 # without having to set additional parameters